Bump protobuf from 3.19.4 to 4.21.2

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 3.19.4 to 4.21.2.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/generate_changelog.py)
- [Commits](https://github.com/protocolbuffers/protobuf/commits)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.in

@@ -4,7 +4,7 @@ cffi==1.15.0
 future==0.18.2
 itsdangerous==2.0.1
 pbr==1.10.0
-protobuf==3.19.4
+protobuf==4.21.2
 pyopenssl==19.1.0
 PyYAML==5.2 # PyYAML 5.3 does not support Python 3.4
 pytz==2021.3

requirements.txt

@@ -30,7 +30,7 @@ itsdangerous==2.0.1
     # via -r requirements.in
 pbr==1.10.0
     # via -r requirements.in
-protobuf==3.19.4
+protobuf==4.21.2
     # via -r requirements.in
 pycparser==2.18
     # via cffi

setup.py

@@ -20,7 +20,7 @@
     install_requires=[
         "deprecated==1.2.13",
         "cryptography>=2.2.1",
-        "protobuf==3.13.0",
+        "protobuf==4.21.2",
         "requests>=2.11.1",
         "future>=0.18.2",
         "asn1==2.2.0",